DE112005000501T5 - Grease composition and method of making the same, and rolling bearings having the grease composition included therein - Google Patents

Abstract

Grease composition comprising a base oil, a thickener and a high pressure agent containing sulfur in a molecular structure thereof, wherein the extreme pressure agent is so to the base oil is added, so that the product of the amount (mgS / g) of in the extreme pressure agent contained active sulfur and the addition amount (wt .-%) of Extreme pressure agent, based on the total amount of the grease composition, in a range of 3 to 13.

Description

TECHNICAL TERRITORY

The The present invention relates to a grease composition, those in lubricating properties and properties of resistance across from a high load is excellent, a method of manufacture the grease composition and a rolling bearing into which the grease composition filled and more specifically to a grease composition that preferred for a rolling stock, a construction machine, a papermaking machine made of steel, a cartwheel suspension or storage part (car wheel indication part), a rotary joint or a constant velocity joint and the like can be used a manufacturing process for the grease composition and a rolling bearing into which the grease composition filled becomes.

BACKGROUND STATE OF THE ART

It It is known that when the rolling bearing is enclosed in the grease is a lubricating film used under high load application condition lubricating grease can easily break. When the lubricant film tears, Metal contact occurs, which has the disadvantages of faulty lubrication generates an increase in heat generation and frictional abrasion caused. By using grease, containing an extreme pressure agent or extreme pressure agent (extreme-pressure agent, EP funds), therefore, are the disadvantages caused by Metal contact, prevented. As substances to prevent the above disadvantages described were solid lubricating grease (see Patent Document 1) containing 100 parts by weight of an adduct of melamine (iso) cyanurate and 5-1000 Parts by weight of a solid lubricant selected from the group of polytetrafluoroethylene, molybdenum disulfide and molybdenum dithiocarbamate (hereinafter abbreviated as MoDTC) (see Patent Document 1). To reduce the abrasion, Also, a grease composition (see Patent Document 2) containing molybdenum dithiocarbamate and Polysulfide disclosed.

If the grease composition for used the rolling bearing and the double joint or constant velocity joint will that for a rolling resource, the construction machine, the papermaker made of steel, the carriage wheel suspension or storage part and the like under high load application conditions used to have a conventional Grease composition a problem in that this one has insufficient abrasion-reducing effect. Under heavy Conditions of use, it is necessary, the grease composition in terms of lubricant properties and resistance properties across from High load to improve the metal contact, due to the tearing of the lubricant film occurs to prevent. In the rolling stock is between the rolling surface the inner ring as well as the rolling surface of the outer ring and a "roller", which is a rolling element is, and generated between the flange area and the "roller" sliding friction Sliding friction is greater than the one of the rolling friction it is likely that the breakage or crack of the lubricant film occurs at the flange portion.

in the Ball bearing enters between the rolling element and the housing Slip on and continue to occur between the rolling element and the Bearing ring on a differential sliding. Thus, it is likely that the lubricant oil film of lubricant grease breaks.

When using the extreme pressure agent containing sulfur in a molecular structure thereof, the cracking of the lubricant film is prevented, and the metal surface of the bearing is excessively corroded when the addition amount of the extreme pressure agent is too large, which causes a shortening of the durability of the bearing. In addition, it is necessary to take great effort in repeating a durability test for each extreme pressure agent to determine an optimum addition amount. When a variety of high pressure agents are added to the base oil, it is necessary to conduct many experiments.
Patent Document 1: Japanese Patent Application Laid-Open No. 61-12791 (Scope of Claims).
Patent Document 2: Japanese Patent Application Laid-Open No. 10-324885 (paragraph [0005]).

EPIPHANY THE INVENTION

By the Invention to be solved problem

The The present invention has been made to be as described above Problem to cope. It is an object of the present invention a grease composition, the friction abrasion of a lubricant surface in one High load condition or in a state where sliding movement is generated and for a long period of time, prevents a method of manufacture, which is capable of readily adding the proportion of an extreme pressure agent determine the grease composition, and a rolling bearing, in which the grease composition is included.

MEDIUM TO SOLVING THE PROBLEM

A Grease composition of the present invention comprises Base oil, a thickener and a high pressure agent containing sulfur in one molecular structure thereof. The extreme pressure agent is added to the base oil, so that a product of an amount (mgS / g) of active sulfur, the is contained in the extreme pressure agent, and an addition amount (% by weight) the extreme pressure agent, based on the total amount of the grease composition, in a range of 3 to 13.

Not less than two types of extreme pressure agents are added to the base oil. A product of an amount (mgS / g) of active sulfur present in each the high pressure agent is contained, and an addition amount (% by weight) of each of the extreme pressure agents, based on a total of Grease composition is noted. The high pressure agents become the base oil so admitted that the sum of the calculated products for all High pressure agent is in a range of 3 to 13.

Of the Thickener is a urea compound.

The Amount (mgS / g) of the active sulfur is a value obtained by the following method, as a scale indicating the degree of reactivity of the extreme pressure agent, containing sulfur in one of its molecular structures, with a metal surface indicates.

0.5 g copper powder (manufactured by KANTO CHEMICAL Co., INC., particle diameter: 75 to 150 μm), 4.75 g of mineral oil (100 cSt., 40 ° C, "Super Oil N100 "produced from NIPPON OIL CORPORATION) and 0.25 g of the extreme pressure agent containing Pigs in a molecular structure thereof were placed in a test tube and solved. Then these were at 150 ° C in the air for stirred for four hours. The concentration (wt%) of sulfur before and after the test becomes with fluorescence X-ray analysis measured and the amount of active sulfur is from the following Equation (1) is calculated. That is why the amount of active sulfur a value that depends is determined by the type of copper powder and mineral oil, and he distinguished depending on the extreme pressure agent.

[Equation (1)]

• Amount of active sulfur = (x / 100 -y / 100) x 1000 (mgS / g) (1), wherein x indicates the concentration of sulfur (wt%) in the lubricant oil in which the extreme pressure agent is dissolved, and it is a value measured at 150 ° C before stirring, and y indicates the concentration of sulfur (wt. %) in the lubricant oil in which the extreme pressure agent is dissolved, and it is a value measured at 150 ° C after stirring for 4 hours.

As shown in the equation (1), the amount (mgS / g) of the active Sulfur the present invention, the amount (mg) of sulfur in 1 gram of the lubricant oil contained sulfur, which has reacted with the copper powder. As the value of the amount (mgS / g) of active sulfur increases, The sulfur reacts increasingly with the metal surface. The is called, It can be said that the extreme pressure agent with a larger amount is highly reactive with active sulfur.

In order to preferably use the grease composition for a rolling bearing used under high load application conditions, it is necessary to repeat a durability test in order to determine the optimum addition amount of the extreme pressure agent when the grease composition is increased by giving the high pressure agent containing the sulfur in a molecular structure thereof, to the base oil. The extreme pressure agent containing the sulfur in its molecular structure is believed to form a thin sulfide film on the metal surface of the bearing, thereby maintaining lubricant performance. Of the sulfur contained in the extreme pressure agent, a portion of the sulfur reacts with the metal surface to form the sulfide layer. The reactivity of the extreme pressure agent differs according to its molecular structure. Therefore, it is considered that the addition amount of the high-pressure agent having high reactivity is necessarily small, whereas the addition amount of the high-pressure agent having a low reactivity is necessarily large.

The The present invention has been based on the above-described Knowledge made. As a scale, the degree of reactivity of the im High pressure agent containing sulfur indicates the amount of active sulfur, based on the measuring method described above, calculated. Hereinafter, the addition amount of the extreme pressure agent in set such a way that the product of the Amount of active sulfur and the amount of added high pressure agent is constant in a range in which the obtained grease composition sufficient lubricant performance in high load application condition having.

The Product of the amount (mgS / g) of the active sulfur and the amount added (Wt%) has the unit (mgS / g x wt%). In the present Invention, the product is used as an index to determine the amount of addition of the extreme pressure agent, and the indication of the unit becomes omitted.

By Finding the product of the amount of active sulfur and the amount added, as described above, it is possible the grease composition containing the extreme pressure agent, to assess the sulfur in its molecular structure.

One Method of the present invention for producing a grease composition comprising a step of adding a thickener and an extreme pressure agent, containing sulfur in a molecular structure thereof, to the base oil. The extreme pressure agent becomes the base oil added so that the product of the amount (mgS / g) of active sulfur, which is contained in the extreme pressure agent, and the amount added (wt .-%) the extreme pressure agent, based on the total amount of the grease composition, in a range of 3 to 13.

In a rolling bearing of the present invention into which the grease composition filled is the lubricating grease composition described above in one including sliding region thereof.

EFFECT OF INVENTION

In The grease composition of the present invention will be the Extreme pressure agent containing the sulfur in a molecular structure hereof, to the base oil added so that the product of the amount (mgS / g) of the active sulfur, which is contained in the extreme pressure agent, and the addition amount (% by weight) of Extreme pressure agent, based on the total amount of the grease composition, is in the range of 3 to 13. Therefore, the grease composition in terms of wear resistance and durability excellent. Furthermore, the addition amount of the High pressure agent, based on the amount of active sulfur, determined become. Thus, when a new additive is used, it is possible to annoy the Carrying out of Trial-and-error attempts for to reduce the amount to be added.

If not less than two kinds of the extreme pressure agent added to the base oil the product of the amount (mgS / g) of active sulfur, which is contained in each of the extreme pressure agents and the addition amount (% By weight) of each of the extreme pressure agents, based on the total amount of the grease composition. The addition amount of each Extreme pressure agent can be specified so that the sum of the products, the for all the extreme pressure agent is calculated, is in the range of 3 to 13. So this is easy for to design the production of the grease composition.

in the Process of the present invention for the preparation of the grease composition is the extreme pressure agent containing sulfur in its molecular Structure, to the base oil added so that the product of the amount (mgS / g) of the high pressure agent containing active sulfur and the addition amount (% by weight) of the extreme pressure agent, based on the total amount of grease composition, in the range from 3 to 13 lies. Therefore, the grease composition is the wear resistance and Durability of this excellent.

in the Roller bearing of the present invention, in which the grease composition filled is the above-described grease composition in the including sliding region thereof. Therefore, the grease composition in terms of wear resistance and durability thereof, and preferably in the high load application state be used.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a partially cut-away perspective view of a rolling bearing.

2 Fig. 10 shows a high pressure property evaluation test apparatus.

3 Fig. 14 shows the relationship between the product of the amount of active sulfur contained in a high pressure agent and the addition amount of the extreme pressure agent and the durability in the high pressure property evaluation test.

1

inner ring

2

outer ring

3

roller

4

casing

5

rotary shaft

6 7

Annular sample

8th

end surface

BEST EMBODIMENT FOR IMPLEMENTATION THE INVENTION

The Grease composition of the present invention is characterized by Add a thickener and a sulfur in its molecular Structure containing high pressure agent to the base oil in such a way and Obtain the product of the amount (mgS / g) in the high pressure medium contained active sulfur and the addition amount (wt .-%) of the extreme pressure agent, based on the total amount of grease composition, in the range from 3 to 13 lies. Therefore, it is possible to know the type of high pressure agent and to arbitrarily select the amount of addition thereof, provided that the Product of the amount (mgS / g) of active in the extreme pressure agent Sulfur and the addition amount (wt .-%) of the extreme pressure agent in the range from 3 to 13 lies.

Not less than two types of extreme pressure agent can be added to the base oil become. In this case, a product of an amount (mgS / g) is added to in each of the high pressure active sulfur and a Addition amount (% by weight) of each of the extreme pressure agents, based on a total amount of the grease composition. The High pressure agents become the base oil added in such a way that the sum of the calculated products for all the high pressure agent is in the range of 3 to 13.

As the extreme pressure agent containing the sulfur in a molecular structure thereof, which can be used in the present invention, there are listed:
Sulfurized grease, sulfurized olefin, sulfurized ester, molybdenum dithiocarbamate, zinc dithiocarbamate, zinc dithiophosphate and molybdenum dithiophosphate and mixtures of not less than two kinds of these specified extreme pressure agents. When poly-α-olefin oil is used as the base oil of the present invention, which will be described later, it is particularly preferable to use sulfurized grease, sulfurized olefin, molybdenum dithiocarbamate and zinc dithiocarbamate because these extreme pressure agents are excellent in solubility in the base oil.

When the sulfurized grease becomes sulfurized lard, sulfurized Rapeseed oil, sulfurized castor oil, sulfurized soybean oil, sulfurized rice bran oil listed. As commercially available Products are "Lubrizol Lz5346 "(trade name, manufactured by Lubrizol Corporation) and "Lubrizol Lz5006" (trade name, manufactured from Lubrizol Corporation).

When the sulfurized olefin is listed as propylene, isobutene, diisobutene. As commercially available Products become "Anglamol 33 "(trade name, manufactured by Lubrizol Corporation), "Anglamol 3310" (trade name, manufactured from Lubrizol Corporation).

When commercially available molybdenum can "Molyvan 822 "(trade name, manufactured by Vanderbuilt Company, Inc.). As commercially available Zinc dithiocarbamate can "Vanlube AZ "(trade name, manufactured by Vanderbuilt Company, Inc.).

When the base oil, that for the grease composition of the present invention is used can be, be mineral oil, Poly-α-olefin oil, ester oil, phenyl ether oil, fluorine oil and hydrocarbon oil (GTL base oil) synthesized by Fischer-Tropsch reaction, listed. Of these oils For example, it is preferred to include at least one base oil selected from the poly-α-olefin oil and the Mineral oil, to use. Normally, the poly-α-olefin oil described above provides oligomers of α-olefin or isomerized α-olefin or mixtures of polymers. As examples of the α-olefin Is it possible List: 1-octane, 1-nonene, 1-decene, Dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 1-docoses and 1-tetracoses. Usually blends used of these substances. As the mineral oil, it is possible to use any lubricant, like paraffin mineral oil, Naphtenmineralöl and the like and those involved in the decomposition of grease used to insert.

It is preferable that the base oil used in the present invention has a kinematic viscosity of 30 to 200 mm ² / s at 40 ° C. It is not preferable that the base oil has a kinematic viscosity of less than 30 mm ² / s, since the evaporation loss thereof increases and the resistance to heat is impaired. It is not preferable that the kinematic viscosity of the base oil exceeds 200 mm ² / s because the temperature of the bearing greatly increases due to an increase in the rotational torque.

(R₂ in der Formel (1) bedeutet eine zweiwertige aromatische Kohlenwasserstoffgruppe mit 6 bis 15 Kohlenstoffatomen. R₁ und R₃ bedeuten eine aromatische Kohlenwasserstoffgruppe mit 6 bis 12 Kohlenstoffatomen, eine alicyclische Kohlenwasserstoffgruppe mit 6 bis 20 Kohlenstoffatomen oder eine aliphatische Kohlenwasserstoffgruppe mit 6 bis 20 Kohlenstoffatomen. R₁ und R₃ können identisch oder voneinander verschieden sein).As a thickener which can be used for the grease of the present invention, it is possible to use metal soap-based thickeners such as aluminum soap, lithium soap, sodium soap, lithium composite soap, calcium composite soap, aluminum composite soap and the like, and a urea compound such as a diurea compound and a polyurea compound , to use. Taking the heat resistance into consideration, the urea compound is preferable. The diurea compound shown by the formula (2) shown below is particularly preferable. These thickeners may be used singly or in combination of two or more. [Chemical Formula 1]

(R ₂ in the formula (1) means a divalent aromatic hydrocarbon group having 6 to 15 carbon atoms. R ₁ and R _{3 represent} an aromatic hydrocarbon group having 6 to 12 carbon atoms, an alicyclic hydrocarbon group having 6 to 20 carbon atoms or an aliphatic hydrocarbon group having 6 to 20 carbon atoms, R ₁ and R ₃ may be identical or different from each other).

If the number of carbon atoms of R _{2 is} less than the above-described range, the thickening properties of the grease are deteriorated. On the other hand, if the number of carbon atoms of R _{2 is} more than the above-described range, it is likely that the grease composition will be cured. As R ₂ , groups composed of aromatic monocyclic rings or aromatic polycyclic rings linked together through a methylene group, a cyanurring group or an isocyanuric ring group are listed.

When the number of carbon atoms of R ₁ and R _{3 is} smaller than the above-described range, the heat resistance properties of the grease composition are deteriorated. When the number of carbon atoms of R ₁ and R _{3 is} larger than the above-described range, the thickening properties of the grease composition are deteriorated. As the aromatic hydrocarbon group denoted by R ₁ and R ₃ , a phenyl group, triyl group, xylyl group, t-butylphenyl group and a benzyl group. As the alicyclic hydrocarbon group, a cyclohexyl group, methylcyclohexyl group and dimethylcyclohexyl group are listed. As the aliphatic hydrocarbon group, straight-chain alkylamino compounds are preferred. For example, n-docosylamine, n-octylamine, n-icosylamine are listed.

Of the Blend proportion of the urea compound is 5 to 30 wt .-% adjusted, based on the total lubricating grease composition. If the mixing ratio of the urea compound is less than 5% by weight is, the thickening effect is reduced and greasing becomes difficult. On the other hand, if the mixing ratio of the urea compound more than 30% by weight, it is difficult, the desired To get effect.

The Grease composition of the present invention may, if necessary, known additives except contain the high pressure agent. As additive means it is possible to list: Antioxidants, such as amine-based antioxidants, antioxidants Phenol-based; Metal-inert agents, such as benzotriazole, sodium nitrite and the same; viscosity index improving Agents such as polymethacrylate, polystyrene and the like; and solid Lubricants, such as molybdenum disulfide, Graphite and the like. These additive agents can be used for base oil added singly or in combination of two kinds and more thereof become.

A rolling bearing incorporating the grease composition produced by the production method of the present invention will be described below with reference to FIG 1 described. 1 is a partially cut-away perspective view of the rolling bearing. In the rolling bearing becomes a roller 3 between an inner ring 1 and an outer ring 2 over a housing 4 arranged. The roller 3 is subject to rolling friction between a rolling surface 1a of the inner ring 1 and a rolling surface 2a of the outer ring 2 and sliding friction between the flange sections 1b of the inner ring 1 , To reduce rolling friction and sliding friction, the grease composition of the present invention is included herein.

EXAMPLES

Examples 1 to 10, Comparative Examples 1 to 4

When the sulfur-containing extreme pressure agent became the amount (mgS / g) of active Sulfur of the sulfurized grease, sulfurized olefin, molybdenum dithiocarbamate, Zinc dithiocarbamates, based on the equation (1), respectively. Table 1 shows the results. Table 1 also shows the range the amount of addition (% by weight) of each extreme pressure agent which makes it possible to that the product of the amount (mgS / g) of the active sulfur and the Addition amount (% by weight) of the extreme pressure agent in the range of 3 to 13 lies.

In each of Examples 1 to 6 and Comparative Examples 1 to 4, an experimental grease composition was prepared by adding the above-described high pressure lithium grease / mineral oil grease (kinematic viscosity: 100 mm ² / s at 40 ° C, mixture consistency 220). prepared in the proportions shown in Table 2.

In each of Examples 7 and 8, an experimental grease composition was prepared by adding the extreme pressure agents having the ratios shown in Table 2 to urea / PAO grease A obtained by reacting 60.6 g of 4,4'-diphenylmethane diisocyanate, 31 , 3 g of octylamine and 66.2 g of stearilamine with each other in 2000 g of the poly-α-olefin (SYNFLUID 801, manufactured by Nippon Steel Chemical Co., Ltd .: kinematic viscosity: 46 mm ² / s at 40 ° C) ,

In each of Examples 9 and 10, an experimental grease composition was prepared by adding the extreme pressure agents having the ratios shown in Table 2 to urea / PAO grease B obtained by reacting 200.8 g of 4,4'-diphenylmethane diisocyanate and 159.2 g cyclohexylamine with each other in 1640 g of the poly-α-olefin (SYNFLUID 801, manufactured by Nippon Steel Chemical Co., Ltd.: kinematic viscosity: 46 mm ² / s at 40 ° C) prepared.

In In each of the examples, the product of the amount (mgS / g) of the active one fell Sulfur and the amount of addition (% by weight) in the amounts shown in Table 1 Range, whereas in the comparative examples the product does not fell into the area.

One High pressure property evaluation test and a rolling bearing test were performed on the obtained grease compositions. table 2 shows the results.

HIGH PRESSURE PROPERTY ASSESSMENT TEST

A high pressure property evaluation test apparatus is disclosed in 2 shown. The evaluation test apparatus is made of an annular sample body 6 constructed with a diameter of 40 × 10, fixed on a rotating shaft 5 and an annular specimen 7 whose end surface has an end surface 8th of the specimen 6 is rubbed. The grease composition becomes on the end surface 8th applied. The high pressure properties were achieved by rotating the rotary shaft 5 at 2000 rpm and set an axial load of 490 N in the direction A in 2 and a radial load of 392N. The high pressure properties were measured by measuring vibrations of the rotating shaft 5 judged by a vibration sensor. The test was carried out until the vibration value of the rotation shaft 5 twice the initial value. The period of time required for the vibration value to become twice the initial value was measured.

TEST OF THE ROLL BEARING

• ¹⁾ Lubrizol Lz5346 (hergestellt von Lubrizol Corporation)
• ²⁾ Anglamol 33 (hergestellt von Lubrizol Corporation)
• ³⁾ Molyvan 822 (hergestellt von der Vanderbuilt Company, Inc.)
• ⁴⁾ Vanlube AZ (hergestellt von der Vanderbuilt Company, Inc.)

Tabelle 2

• ¹⁾ Lubrizol Lz5346 (hergestellt von Lubrizol Corporation)
• ²⁾ Anglamol 33 (hergestellt von Lubrizol Corporation)
• ³⁾ Molyvan 822 (hergestellt von der Vanderbuilt Company, Inc.)
• ⁴⁾ Vanlube AZ (hergestellt von der Vanderbuilt Company, Inc.)
• ⁵⁾ Lubrizol Lz1097 (hergestellt von Lubrizol Corporation)

3.6 g of grease was sealed in each of the 30206 conical roller bearings, and the evaluation tester was operated at an axial load of 980 N, 2600 rpm and room temperature to measure the temperature of the surface of the flange portion during rotation. An average value of the temperature of the surface of the flange portion was calculated in 4 to 8 hours after the operation of the evaluation tester was started. Table 1

• ¹⁾ Lubrizol Lz5346 (manufactured by Lubrizol Corporation)
• ²⁾ Anglamol 33 (manufactured by Lubrizol Corporation)
• ³⁾ Molyvan 822 (manufactured by Vanderbuilt Company, Inc.)
• ⁴⁾ Vanlube AZ (manufactured by Vanderbuilt Company, Inc.)

Table 2

• ¹⁾ Lubrizol Lz5346 (manufactured by Lubrizol Corporation)
• ²⁾ Anglamol 33 (manufactured by Lubrizol Corporation)
• ³⁾ Molyvan 822 (manufactured by Vanderbuilt Company, Inc.)
• ⁴⁾ Vanlube AZ (manufactured by Vanderbuilt Company, Inc.)
• ⁵⁾ Lubrizol Lz1097 (manufactured by Lubrizol Corporation)

Looking at Examples 1 to 10 and Comparative Examples 1 to 4 shows 3 the relationship between the product of the amount (mgS / g) of the active sulfur and the addition amount (% by weight) and the life in the high-pressure property evaluation test. In 3 the abscissa axis indicates the product of the amount (mgS / g) of the active sulfur and the addition amount (% by weight) and the ordinate axis shows the life (hours) in the high-pressure property evaluation test.

As in Table 2 and 3 The grease composition was obtained by adding the sulfurous high pressure agent to the base oil so that the product of the amount (mgS / g) of the active sulfur contained in the high pressure agent and the addition amount (% by weight) of the high pressure agent is in the range of 3 to 13. Therefore, the grease composition had improved wear resistance. As in 3 As shown, the lubricating grease compositions have a long life and are therefore preferable when the amount (mgS / g) of the active sulfur contained in the high pressure agent and the addition amount (% by weight) of the extreme pressure agent are in the range of 4 to 10.

The grease composition included in the bearing of each of the examples in the bearing was obtained by adding the sulfur-containing high pressure agent to the base oil so that the product of Men Ge (mgS / g) of the active sulfur contained in the high pressure agent and the addition amount (wt .-%) in the range of 3 to 13. Therefore, heat was generated only to a small extent in the flange portion of each bearing and metal contact of the sliding portion was prevented. Therefore, the bearing of each example is durable.

INDUSTRIAL APPLICABILITY

The The grease composition of the present invention is as regards Wear resistance outstanding, durable and preferably used in high load application conditions become. Therefore, the grease composition of the present Invention in rolling bearings, such as a cylindrical roller bearing, a conical roller bearings, a self-aligning roller bearing, a acicular Rolling bearing, a cylindrical thrust roller bearing, a conical Thrust roller bearing, a needle-shaped thrust roller bearing, a self-aligning thrust roller bearing and a ball bearing be included.

Summary

The The present invention provides a grease composition the frictional abrasion of a lubricant surface in a high load application condition or in a state where sliding motion is generated and for one long period of time, prevents a manufacturing process, that for easy determination of the addition rate of an extreme pressure agent the grease composition is capable, as well as a roller bearing, in which the grease composition is included. The grease composition is achieved by adding a thickener and an extreme pressure agent, containing sulfur in a molecular structure thereof, to the base oil. The extreme pressure agent is added to the base oil so that the product the amount (mgS / g) of active sulfur contained in the extreme pressure agent, and the addition amount (% by weight) of the extreme pressure agent, based on the Total amount of grease composition, in the range of 3 to 13 lies.

Claims (7)

A grease composition comprising a base oil, a Thickener and a high pressure agent containing sulfur in one molecular structure thereof, wherein the high pressure agent is added to the base oil so so that the product of the amount (mgS / g) of high-pressure agent contained active sulfur and the amount of addition (wt.%) of the extreme pressure agent, based on the total amount of the grease composition, in one Range from 3 to 13 lies. A grease composition according to claim 1, wherein not less than two kinds of extreme pressure agents added to the base oil with the product of the amount (mgS / g) of active sulfur, contained in each extreme pressure agent and the amount of addition (% By weight) of each of the extreme pressure agents, based on the total amount the grease composition is detected; and the high pressure agents to the base oil be added so that the sum of the products for all High pressure agent can be calculated in a range of 3 to 13 lies. A grease composition according to claim 1, wherein the high pressure agent is at least one extreme pressure agent selected from sulfurized grease, sulfurized olefin, ester sulfide, molybdenum dithiocarbamate, Zinc dithiocarbamate, zinc dithiophosphate and molybdenum dithiophosphate. A grease composition according to claim 1 or 2, wherein the thickener is at least one thickener selected from a urea compound or a metal soap. Process for the preparation of a grease composition, comprising a step of adding a thickener and a Extreme pressure agent, the sulfur in a molecular structure thereof has, to the base oil, wherein the high pressure agent is added to the base oil so that the Product of the amount (mgS / g) of active sulfur that is in the extreme pressure agent is contained, and the addition amount (wt .-%) of the extreme pressure agent, based on the total amount of grease composition, in one range from 3 to 13 lies. Rolling bearing comprising an inner ring; an outer ring; a plurality of rolling elements arranged between the inner ring and the outer ring; and a grease composition included in a periphery the rolling elements, wherein the grease composition is a grease composition according to claim 1, 2 or 3 represents. Rolling bearing according to claim 6, wherein the rolling bearing a Represents ball bearing.